Research On Water Analysis And Treatment Experiment Of Roofing Rainwater Of Chongqing

Sponge city, which is called as a new urban rainwater and flood management measure, has good elasticity when the city facing natural disasters brought by the rain or goordinating the change of environment. It takes actions on water absorption,water seepage, water purification, water storage in rainy days. We put the stored rainwater out when we need, and make use of it. Its international general term is that low impact development of rainwater system building.Especially in such a time that water shortage problem is particularly prominent, the rain, as one of the good quality urban water, get more and more attention of people. The triple effect of rainwater utilization project that is recycling, reducing the pollution and the blood, has a certain advantage compared with other water saving methods. In the urban roof rainwater pollutant concentration is relatively low, the water quality is relatively good, treatment process is relatively simple, low treatment cost. Therefore, the paper has the high feasibility and practicability on the study of typical roof rainwater utilization in chongqing.According to the rainwater runoff quality inspection and analysis of the asphalt roof, planting roof, and PC board canopy in chongqing area, we can know that the water quality of roof runoff in chongqing has several important features: the initial rain runoff pollution is serious, after the 8 mm abandon flow, the pH is between 6-8,the turbidity is between 10-40 NUT, the COD is between 80-200mg/L, the TN is between 6-15mg/L, the TP is between 0.5-1.2 mg/L.SS removal rate is 40%- 60%, turbidity removal rate is 20%- 50%, COD removal rate of 30%-60%. After abandon flow, the suspended solid, organic matter of the rainwater has a low concentration, and the content of nitrogen and phosphorus in the water has a low value, and has a low biochemical possibility(COD/BOD5?0.2), the SS in the rainwater, it is relatively low and can be directly in precipitation-filtration or filtration to get a removal effect after coagulation precipitation. COD content is relatively high, and reduction treatment of the COD need to be down. In view of the roof rainwater quality characteristic, this paper chose the "coagulation-sedimentation- filtration- activated carbon adsorption" and "presedimentation-filtration- activated carbon adsorption" two physical chemistry treatment technology for water treatment process.First, before the device design, its rate of abandoned flow is 8 millimeter by analyzing rainwater collection. Secondly, coagulation sedimentation beaker experiment is carried out, It's need to determine the best kinds of coagulation agent, coagulant and dosage, coagulation time, precipitation time. Analysis of the main design parameters of rainwater treatment plant coagulation precipitation phase, and we can know coagulation agent is PAC, dosage is 0.1 g/L, the coagulation time is 20 minutes, precipitation time is 20 minutes.Running results show that the "coagulation- sedimentation- filtration- activated carbon adsorption technology" and "presedimentation- filtration- activated carbon adsorption technology" is applied to water treatment reusing. Treated water quality meet the reuse of urban recyccling water- water quality stantard for urban miscellaneous water consumprion(GB/T 18920-2002), the reuse of urban recyccling water-water quality stantard for scenic environment use(GB/T 18921-2002).